Long Term Performance Monitoring of the Lamont Test Road

Roadway agencies in northern climates are well aware of pavement deterioration problems and the accompanying maintenance expenses associated with living in a cold weather environment. One common such problem is the development of low temperature transverse cracking. To truly build long-life pavements, design procedures must be improved for the selection of better crack resistant materials. Significant efforts were initiated in the early 1990s in support of the Canadian Strategic Highway Research Program (C-SHRP) towards the construction of three Canadian test roads, located at Lamont (Alberta), Hearst (Ontario) and Sherbrooke (Quebec). The main objective was to enhance the understanding of the asphalt cement characteristics related to low temperature cracking and to correlate the then newly published Canadian General Standards Board (CGSB) specification for asphalt cement (CAN/CGSB-16.3-M90) to field performance. This paper deals with the design, construction, and monitoring activities of the main test road constructed in 1991 near Lamont. For that road, seven different test sections were constructed each using a markedly different grade of asphalt cement for each section. The asphalt cements were tested and classified according to the CGSB specification, as well as, the Superpave Performance Grade (PG) system. While none of the test sections included a polymer modified asphalt, two of the sections used modified asphalt cements that were oxidized or air blown for improved temperature susceptibility characteristics. On-site ambient and pavement temperature monitoring was collected during the first three winters of service. Temperature data from a local weather station has also been collected for subsequent years. The general pavement condition and transverse crack counts for the test sections have been monitored through yearly site inspections. This report also includes wheel path rutting and pavement ride quality data that has been collected by high speed survey vehicles. After twelve winters of service, it is now possible to provide some ìlong termî performance results from the Lamont Test Road. The asphalt cement contribution to pavement performance is clearly evident when reviewing the wide range of observed transverse cracking frequencies. These vary from a virtual crack free pavement of two cracks per kilometre to a highly distressed pavement with 180 cracks per kilometre. Other indications on the influence of asphalt cement quality towards pavement performance are also documented.